This invention relates to a cable winch hoisting device for theatrical stages. The invention solves the problem of designing such a device so that it has a simple, space-saving construction and can be operated in an abundant variety of functions.
The invention comprises a winch hoisting device for theatrical stages, whereby a plurality of elongated, rod-like holding girders are suspended on cables, and these holding girders are adjustable in height by varying the free cable length between the cable suspension and the holding girder, which determines the position of the respective holding girder. The holding girders are adjustable in height between two end positions without any mutual interference in the clearance spaces which do not overlap with one another and are provided for the holding girders. At least two cables which are uniformly adjustable by the same cable-operating device act on the holding girders and are distributed over the length of the girders. The cable-operating devices are each electrically driven cable drums. The cables acting on the same holding girder can be wound up side by side onto the cable drum of the respective cable-operating device with the same change in free cable length, which determines the position of the holding girder. The device is designed to be especially space-saving and functionally versatile with a simple structural design.
The invention is based on the general idea of using drive devices with an especially shallow design in cable-operating devices, and having these drive devices encompassed as completely as possible by a respective bowl-shaped cable drum. The width of the cable-operating devices in the axial direction of the drums is determined essentially by the width of the drums. In this way, the multiple cables required for a holding girder run in close proximity, where each drum of a cable-operating device guides all the cables belonging to one hoisting girder.
In the case of holding girders in close proximity to one another to be mounted on the stage space, the cable-operating devices according to this invention can be designed in rows situated one above the other with cables guided in planes one above the other. With the arrangement in two rows lying one above the other, the cable-operating devices can be arranged with an offset with a mutual gap. The cables from the cable-operating devices in the lower row respectively may be passed beneath the cable-operating devices and their fastenings in the row above that with no problem. The cables may also be guided in different planes after horizontal deflection at the upper end of the stage space.
The cable-guiding drums of the cable-operating devices may preferably be made of plastic.
Mechanically operable means for emergency operation of the brakes of these operating devices can project outward through the gaps between cable-operating devices situated side by side.
The respective drive device of the cable-operating devices may be a synchronous motor which is energized by a permanent magnet and whose torque is transmitted via a gear to the cable drum. The gear is expediently designed as a planetary gear.
Each drive device may be equipped with an independent, integrated frequency regulator. However, an especially advantageous design is one in which several drive devices are operated with the same frequency regulator and a circuit using a bus system, for example, is provided for this purpose.